In the fabrication of HDD media, substrates are cleaned after multiple polish steps and before film depositions. With ever-increasing areal density the substrate need to be extremely clean and free of any residue from prior fabrication steps or environments. Any such, residue will cause disk failure and results in lower yield and higher cost. It is therefore important to provide an efficient and thorough cleaning process, whilst maintaining the rate of processing the media (parts per hour; PPH).
A shortcoming of such an approach lies in the media having an inconsistent rotation due to the single point of contact with the conveyor belt. Conveyor belt also stretches over time and results in disk slippage. Another shortcoming due to single point contact is the inconsistent disk position within the guiding rollers, and this results in inconsistent pick and place of the disk.
Another shortcoming is that the scrubbing position on the disk is fixed, and one cannot preferentially scrub different positions on the surface of the disk. This is needed as substrates are handled via the outside diameter (OD) in most of the disk processing steps and as result the OD of the substrates may be more prone to particles, residues and stains.